Conventionally, a wind power generation device has been known in which wind power is received by a blade connected to the main shaft to thereby rotate the main shaft, the rotation of the main shaft is increased in speed by a speed increaser and transmitted to the drive shaft of the power generator and a rotor connected to the drive shaft is rotated to thereby generate power.
In this type of wind power generation device, since power generation efficiency deteriorates if the number of rotations of the drive shaft of the power generator decreases due to reduction in wind power, a one-way clutch is provided between the output shaft of the speed increaser and the drive shaft of the power generator and even if the speed of the rotation on the output shaft side decreases, power generation efficiency is maintained by cutting off the one-way clutch so that the drive shaft side is rotated by the inertia of the rotor (for example, see Patent Document 1).
Moreover, since misalignment such as decentering or angle deviation sometimes occurs between the output shaft of the speed increaser and the drive shaft of the power generator, to absorb this, the output shaft and the drive shaft are sometimes connected through a shaft coupling having an elastically deformable link member (elastic coupling member) made of a synthetic resin (for example, see Patent Document 2).